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Why scale models are ineffective

Actually models are good to predict full scale results, as long as you apply the correct scale factors. The resistance of a ship/model moving in the interface water/air, for example, depends on friction (surface drag) and shape (waves, etc being created), which scale differently but as long you adjust the speed and know what you are measuring you can predict full scale pretty good.

A moving ship impacting a big wave in interface wavy sea/air and associated load is more complex to model. Too many different scale factors! How to fake such a scale model test is described at http://heiwaco.tripod.com/eapp2.htm. Same company, SSPA, also recently faked model tests of the sinking of same the model; http://heiwaco.tripod.com/news.htm .

So scale models are not ineffective ... but very easy to fake.
 
Dave Rogers said:
Yes, these are both valid points. However, we then go on to what the truthers' response to these modifications would be. Suppose we construct a 1/10 scale model of the WTC, then reduce the strength of the main structural members by a factor of 10, and show that the model collapses in a similar manner to the real structure. Will the truth movement's response be "OK, that was a valid modification to compensate for the effects of scaling on the strength-to-weight ratio of the structure? Or will it be, "This test was invalid because the model was deliberately weakened in order to ensure collapse"?

Dave
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lol, their argument would be that you painted mini-nano-thermite on your model and detonated it by remote control.
 
deep44 said:
If the modifications were defined/documented/published before the construction of the model, and they remained unchanged for the duration of the test, then I would either disagree with the modifications before construction started or accept the results of the test.

In other words, I would have a problem if the modifications were changed after testing began, for whatever reason.
Click to expand...

One use of models is to economically test a range of dimensions to find the optimal value for some criteria. Minimal air drag for plane or car would be a good example.


(There are lots of pontificating amateurs around here.)
 
You misunderstood my point about the box columns, however it's not important as I see the dilemma between choosing a model which produces a similar strength to weight ratio, or a model that replicates similar forces.

There is still a problem with the towers' falling, especially World Trade 7: finding an instance in history where fire accomplishes what only a well planned, properly executed controlled demo has done.
 
Scott_Milner said:
There is still a problem with the towers' falling, especially World Trade 7: finding an instance in history where fire accomplishes what only a well planned, properly executed controlled demo has done.
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No, there's not a problem. Unless you are saying buildings do not collapse due to fire?
 
I don't think Heiwa has even commented on a video I showed him of C destroying A without the need for explosives.
 
Heiwa said:
Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!
See http://heiwaco.tripod.com/nist1.htm#6 .

Any ideas what went wrong in my experiment?
Click to expand...


Have you done that risk assessment/method statement for children using flammable liquids yet?

Dave_46

ETA or will you just ignore this, as you have done before?
 
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Heiwa said:
Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!
See http://heiwaco.tripod.com/nist1.htm#6 .

Any ideas what went wrong in my experiment?
Click to expand...

yes



Steel framed building, office contents fire, fought by firefighters. Steel parts collapsed.

ETA - Last comment on blatant derail.
 
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deep44 said:
If the modifications were defined/documented/published before the construction of the model, and they remained unchanged for the duration of the test, then I would either disagree with the modifications before construction started or accept the results of the test.
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That's fine, if a set of modifications could be arrived at which you agreed with. It might not be possible even to get to that point.

Because there's more to it than the square-cube law; there's the gravitational potential energy, which varies as the fourth power of the dimensions, and the buckling resistance of the columns, which varies linearly. Energy absorbed in buckling goes as buckling stress times length, so that varies as the square of the linear dimension. So, in a one-hundredth scale model, for example, do we increase the weight by a factor of a hundred to compensate for the strength-to-weight ratio, but then find that collapse is arrested because the energy balance is now biased by a hundred times in favour of survival? Or do we increase the weight by ten thousand times to get the energy balance right, and then find that the structure can't support even a few per cent of its own static weight?

It seems to me that collapse progression scales differently to collapse initiation. And that, actually, is a far more fundamental problem than the square-cube law. If everything scaled the same, we could correct for it; but different properties scale differently with the same variables.

Dave
 
Heiwa said:
But not really upper part C crushing down lower part A. It seems there was nothing below the roof, part C, to crush down!
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Why do you have lie all the time ? you said

Heiwa said:
Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!
See http://heiwaco.tripod.com/nist1.htm#6 .

Any ideas what went wrong in my experiment?
Click to expand...

You said nothing about crushing you said collapse, so why are you now lying and trying to pretend you said crush ?

Stop derailing this thread with your lies and pathetic attempts to move goalposts.
 
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stateofgrace said:
Why do you have lie all the time ? you said



You said nothing about crushing you said collapse, so why are you now lying and trying to pretend you said crush ?

Stop derailing this thread with your lies and pathetic attempts to move goalposts.
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Could you, please, provide a structure in any size and demonstrate the amazing process you suggest is natural, normal and possible!
 
Heiwa said:
Could you, please, provide a structure in any size and demonstrate the amazing process you suggest is natural, normal and possible!
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You have been provided with a structure that collapsed due to fire, that fact you ignored it is your problem.

Are you saying the structure did not collapse?

You said

Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!
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The structure collapsed, you as usual are wrong.
 
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Heiwa said:
Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!
See http://heiwaco.tripod.com/nist1.htm#6 .

Any ideas what went wrong in my experiment?
Click to expand...

i guess you missed the part about scale in this thread

also what constitutes a "normal" fire?
how did you measure its temperature
how did you measure the steels temp?
 
Heiwa said:
Well, I have tried to collapse a steel structure using normal fire or worse! Nothing really happened except some local deformations, where the fire was applied. No collapse!...

Any ideas what went wrong in my experiment?
Click to expand...


What went wrong is that you did not perform the experiment, and that you are lying when you claim you did. If you had performed it, you would be able to answer the question of how you measured the temperature of the steel legs to determine that they reached 500 degrees C as you reported. You would have been able to answer it immediately, the first time I asked it.

Respectfully,
Myriad
 
Scott_Milner said:
You misunderstood my point about the box columns, however it's not important as I see the dilemma between choosing a model which produces a similar strength to weight ratio, or a model that replicates similar forces.

There is still a problem with the towers' falling, especially World Trade 7: finding an instance in history where fire accomplishes what only a well planned, properly executed controlled demo has done.
Click to expand...

Derail.

and a bad one.
a debunked one.

first time in history claim? Really? Look up august 1945... prior to then no city had been destroyed by a single bomb before either... after? 2 had.
are atom bombs fake?

start a new thread, or search out one and bring up your bs point.
/derail
 
Scott_Milner said:
There is still a problem with the towers' falling, especially World Trade 7: finding an instance in history where fire accomplishes what only a well planned, properly executed controlled demo has done.
Click to expand...

Except that: (a) no well planned, properly executed controlled demolition has ever dropped a structural steel building anywhere near as large as WTC7, and (b) well planned, properly executed controlled demolitions normally cause a building to fall vertically into its own footprint, which WTC7 did not.

(a) is well known, in that the current world record for structural steel building demolition is still held by the J. L. Hudson department store in Detroit (http://www.controlled-demolition.com/default.asp?reqLocId=4); (b) is evident from the fact that videos of the WTC7 collapse show the building leaning several degrees south in the course of the collapse, and the debris pile spanned a four-lane highway adjacent to the south side of the building, as can be found from searching this forum.

Dave
 
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